4,4&#39;-Isopropylidene-bis(3- and 4-phenyleneoxyphthalic anhydride)

ABSTRACT

Aryloxy dianhydrides are prepared from the hydrolysis of the reaction product of a nitro-substituted phenyl dinitrile with a metal salt of a dihydroxy aryl compound in the presence of a dipolar aprotic solvent.

This application is a continuation-in-part of application Ser. No.108,151, filed Jan. 20, 1971, now U.S. Pat. No. 3,787,475.

This invention is concerned with a new class of aryloxy dianhydrides.Such compositions can be prepared by effecting reaction, in the presenceof a dipolar aprotic solvent, of a mixture of ingredients comprising (1)a benzenoid compound of the general formula ##SPC1##

Where the NO₂ group above can be positioned anywhere on the benzenering, and (2) an alkali metal salt of an organic compound of the generalformula

    Alk--O--R--O --Alk                                         II

where R is a divalent aromatic radical, and Alk is an alkali metal atom.

The invention in particular is concerned with dianhydrides selected fromthe class consisting of (1) the compound4,4'-isopropylidene-bis(3-phenyleneoxyphthalic anhydride, and (2)compounds of the general formula ##SPC2##

Where R' is a member selected from the class consisting of (a) thefollowing divalent organic radicals: ##SPC3##

And (b) divalent organic radicals of the general formula ##SPC4##

Where X is a member selected from the class consisting of divalentradicals of the formulas ##STR1## and --S--, where m is 0 or 1, y is awhole number from 1 to 5, and the divalent bonds of the --O--R'--O--radical are equally situated on the phthalic anhydride end groups, e.g.,in the 3,3-positions or the 4,4-positions.

ARYLOXY DERIVATIVES OF AROMATIC DIACIDS HAVE PREVIOUSLY BEEN PREPARED BYDIFFERENT METHODS. The most common method consists in effecting acopper-catalyzed reaction between an alkali metal phenolate and a haloaromatic compound followed by oxidation of alkyl substituents tocarboxylic acid groups. Thus, M. M. Koton and F. S. Florinski in Zh.Org. Khim., 4, 774 (1968) disclose the preparation of4,4'-dioxyphenylene diphthalic acid by the copper catalyzed reaction oftwo equivalents of potassium-4,5-dimethylphenolate with1,4-dibromobenzene for 4-5 hours at 220°-230° followed by potassiumpermanganate oxidation of the methyl groups to carboxylic acid groups.This method has two major limitations, the first being the knowndifficulty in reproducing copper-catalyzed reactions of alkali metalphenolates with halo aromatic compounds and the high temperaturesrequired to effect these reactions, and the second being that any groupsusceptible to oxidation will be oxidized along with the groups whichare desired to be oxidized.

We have without success attempted to effect direct reaction between anitro derivative of an aromatic diacid and an alkali metal phenolate ina dipolar aprotic solvent. For example, the reaction of sodium phenoxideand 4-nitrophthalic acid failed to give any product corresponding to theformula ##SPC5##

Unexpectedly, we have discovered that although the reaction betweensodium phenolate and the nitro acid will not take place with3-nitrophthalic acid, we are able to make aryloxy derivatives of theseacids if reaction is effected between a metal phenolate, with phthalicacid when the acid is in the form of the correspondingnitrophthalonitrile. This reaction between the metal phenolate and thenitrile usually results in high yields of the phenoxy derivative. Thephthalic derivative can then be obtained by hydrolysis of the cyanogroup. In the case of the aryloxy phthalic acids, various well knownprocedures can be used for conversion to the anhydride form.

By virtue of our invention, we are able to prepare numerous tetrabasicacids by reaction of a compound of formula I with a metal salt offormula II. In effecting the above reactions, it is important that oneuse a dipolar aprotic solvent in the reaction of the cyano derivativesof the compounds of formula I. The particular advantages of ourinvention over the prior art are the mild conditions under whichreactions can be carried out; often room temperature is sufficient toeffect reaction, generally high yields of products are obtained, thecommercially attractive potential of synthesizing aromatic acidscontaining oxidizable groups (which is impractical to accomplish bypresently known prior art methods), and the ability to produce diacidsand dianhydrides of a broad scope.

Among the divalent alkyl radicals which the grouping -- C_(y) H_(2y) mayrepresent are, for instance, methylene, ethylene, trimethylene,isopropylidene (--C(CH₃)₂ --), butylene, amylene, etc. Typical ofdihydroxy diarylene compounds from which the metal salt of formula IImay be prepared by reacting the aforesaid diarylene compound with twomols of an alkali-metal hydroxide may be mentioned:

2,2-bis-(2-hydroxyphenyl)propane;

2,4'-dihydroxydiphenylmethane;

bis-(2-hydroxyphenyl)-methane;

2,2-bis-(4-hydroxyphenyl)-propane hereinafter identified as"bisphenol-A" or "BPA";

1,1-bis-(4-hydroxyphenyl)-ethane;

1,1-bis-(4-hydroxyphenyl)-propane;

2,2-bis-(4-hydroxyphenyl)-pentane;

3,3-bis-(4-hydroxyphenyl)-pentane;

4,4'-dihydroxybiphenyl

4,4'-dihydroxy-3,3',5,5'-tetramethylbiphenyl

2,4dihydroxybenzophenone;

4,4'-dihydroxydiphenyl sulfone;

2,4'-dihydroxydiphenyl sulfone;

4,4'-dihydroxydiphenyl sulfoxide;

4,4'-dihydroxydiphenyl sulfide; etc.

The means whereby the present invention may be practiced can be variedwidely. When dialkali metal salts of formula II are used with thebenzenoid compounds of formula I, the molar ratio is advantageously atleast 2 mols of the compound of formula I per mol of the metal salt offormula II. Excess molar quantities of the compound of formula I overthe molar quantity of the metal salt of formula II may be employedwithout departing from the scope of the invention; thus from 2 to 4 ormore mols of the compound of formula I may be used per mol of the metalsalt of formula II.

In making the metal salts of formula II, it is sometimes advantageous topreform these salts by reacting the corresponding dihydroxy organiccompound with an alkali-metal hydroxide such as sodium hydroxide,potassium hydroxide, etc. For instance, the dialkali metal salt ofbisphenol-A may be obtained by reacting 2 mols of sodium hydroxide permol of bisphenol-A. Persons skilled in the art will have no difficultyin determining how to make the alkali-metal salts of formula II for usewith the compounds of formula I.

Alternatively, the dihydroxy diarylene compound, e.g., the bisphenol,may be converted to its alkali metal salt during reaction with thecompounds of formula I by addition of an alkali metal carbonate inadequate molar concentrations to a reaction mixture composed of thecompound of formula I and the precursor hydroxy aromatic compoundrequired to form the metal salts of formula II.

The conditions of reaction whereby the metal salts of formula II arereacted with the compounds of formula I can be varied widely. Generally,temperatures of the order of about 20° - 150° C. are advantageouslyemployed, although it is possible to employ lower or higher temperatureconditions depending on the ingredients used, the reaction productsought, time of reaction, solvent employed, etc. In addition toatmospheric pressure, superpressures and sub-atmospheric pressures maybe employed, depending upon the other conditions of reaction, theingredients used, the speed at which it is desired to effect reaction,etc.

The time of reaction also can be varied widely depending on theingredients used, the temperature, the desired yield, etc. It has beenfound that times varying from a few minutes to as much as 60 to 80 hoursor more are advantageously employed to obtain the maximum yield.Thereafter the reaction product can be treated in the manner required toeffect precipitation and/or separation of the desired reaction product.Generally, common solvents such as diethyl ether, water, etc., areemployed for the purpose. For purification purposes, the final productcan be redistilled or recrystallized in manners well known in the art.

It is important that the reaction between the compounds of formula I andthe metal salts of formula II be carried out in the presence of adipolar aprotic solvent. The term "dipolar aprotic solvent" is intendedto mean any organic solvent which has no active protons which mayinterfere with the reaction herein described. As will be evident tothose skilled in the art, any dipolar aprotic solvent which is capableof dissolving the reactants and causing intimate contact of the reactioningredients may be used.

Among the preferred aprotic solvents which may be employed in thepractice of this invention are non-acid, oxygen-containing,nitrogen-containing organic solvents. These include but are not limitedto, for instance, N,N-dimethylacetamide, N-methylpyrrolidone,N,N-dimethylformamide, dimethylsulfoxide (DMSO), etc.

The amount of solvent used in the reaction mixture may be varied widely.Generally, on a weight basis, one can employ from 0.5 to 50 or moreparts of the solvent per part of total weight of the reactants, namely,the compounds of formula I and the metal compounds of formula II. Theamount of solvent is not critical, but generally we have found that on aweight basis one can employ from 2 to 20 parts of the solvent per partof the total weight of the compounds of formula I and the metalcompounds of formula II.

Once the tetranitrile of the general formula ##SPC6##

where R' has the meanings given above is formed, it is relatively easy,using techniques well-known in the art, to convert the tetranitrile tothe corresponding tetracarboxylic acid and thereafter dehydrate thetetracarboxylic acid to the corresponding desired dianhydride. Forexample, the tetranitrile can be treated with potassium hydroxide in amixture of aqueous methanol and then heated at reflux for a period oftime to give the tetra acid. Acidification of the tetra-acid reactionmixture with, for instance, hydrochloric acid, permits the tetra-acid toseparate. Thereafter, heating at elevated temperatures, for example, atabout 200° to 300° C. will effect dehydration of the tetra-acid to thecorresponding dianhydride.

In order that those skilled in the art may better understand how thepresent invention may be practiced, the following examples are given byway of illustration and not by way of limitation. Unless otherwisestated, all parts are by weight.

EXAMPLE 1

Bis(3,4-dicyanophenyl)ether of bisphenol-A was prepared as follows. Amixture of 1.71 grams (0.0075 mol) bisphenol-A, 0.6 gram (1.1881 grams50.5% aqueous solution, 0.015 mol) sodium hydroxide, 20 ml.nitrogen-sparged DMSO, and 15 ml. benzene was stirred at reflux undernitrogen over a Dean-Stark trap for 4 hours and the benzene was thenremoved by distillation. The reaction mixture was cooled to roomtemperature and 2.595 grams (0.015 mol) 4-nitrophthalonitrile was added.The mixture was stirred under nitrogen at room temperature for 1.5 hoursand was then poured into 100 ml. of water. The product which separatedfrom the aqueous solution as a white powder was extracted into methylenechloride and the extract was washed with water, dried with sodiumsulfate, and filtered. The solvent was removed and the residue wasrecrystallized from toluene/hexane solution to give 3.1 grams (86%yield) of a white grannular solid, melting point 195°-196° C. Thisproduct was identified as the above compound by infra red and byelemental analyses.

    ______________________________________                                                 Found        Calculated                                              ______________________________________                                        %C         77.6           77.5                                                %H         4.24           4.17                                                %N         11.8           11.66                                               ______________________________________                                    

This compound had the formula ##SPC7##

EXAMPLE 1A

A mixture of 1.2 grams (0.0025 mol) of the bis(3,4-dicyanophenyl) etherof bisphenol-A described in Example 1, 5.61 grams (0.1 mol) potassiumhydroxide, and 20 ml. of aqueous methanol was stirred at refluxtemperature of the mass for seven days after which the mixture wasacidified with hydrochloric acid and the oily liquid which separatedsolidified on standing. The solid material was filtered and dried invacuum. Thereafter, the reaction product was dehydrated by heating it at250° C. and then distilled at 350° C. (0.1 mm.) to give2,2-bis-[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride in about a92% yield. The product which melted at 187°-189° C. was identified ashaving the formula ##SPC8##

as evidenced by the following analyses:

             Found        Calculated                                              ______________________________________                                        %C         71.5           71.5                                                %H         4.01           3.85                                                ______________________________________                                    

EXAMPLE 2

1,4-Bis(3,4-dicyanophenoxy)benzene was prepared by first forming amixture of 1.10 grams (0.01 mol) hydroquinone, 3.56 grams (0.02 mol)4-nitrophthalonitrile, 2.76 grams (0.02 mol) anhydrous potassiumcarbonate, and 15 ml. of dry, nitrogen-sparged DMSO. This was stirredunder nitrogen at room temperature for 24 hours and the mixture waspoured into 200 ml. of water. The precipitate was filtered, washed withwater, dried "in vacuo" and dissolved in 250 ml. boiling acetonitrile.The product crystallized from the acetonitrile as fine pale blue needlesamounting to 2.2 grams (61% yield). The crystallized product wasdistilled at 300°-310° C. (0.05 mm) to yield an oil which solidified oncooling. This solid material was recrystallized from acetonitrile togive 2.1 grams of the desired compound, melting point 255°-257° C. whoseidentity was established by infra red and by elemental analyses.

    ______________________________________                                                 Found        Calculated                                              ______________________________________                                        %C         72.7           72.9                                                %H         2.70           2.75                                                %N         15.6           15.45                                               ______________________________________                                    

EXAMPLE 2A

A mixture of 0.905 gram (0.0025 mol) of the 1,4-bis(3,4-dicyanophenoxy)benzene of Example 2, 5.6 grams (0.1 mol) of potassium hydroxide, and 20ml. of aqueous methanol was stirred at the reflux temperature of themass for about one week. The mixture was acidified with hydrochloricacid, and the tetra-acid derivative separated from the cold aqueoussolution as fine, silvery needles. The latter tetra-acid was dehydratedby heating at 275° C. and was then distilled at 300° C. (0.1 mm.) togive the hydroquinone-bis(4-phthalic anhydride) diether in about a 99%yield. This dianhydride which had a melting point of 264°-266° C. hadthe formula ##SPC9##

as evidenced by the following analyses:

             Found        Calculated                                              ______________________________________                                        %C         65.6           65.7                                                %H         2.6            2.48                                                ______________________________________                                    

EXAMPLE 3

A mixture of 0.93 gram (0.005 mol) 4,4'-dihydroxybiphenyl, 0.4 gram(0.792 gram of 50.5% aqueous solution, 0.01 mol) sodium hydroxide, 20ml. nitrogen-sparged DMSO, and 20 ml. benzene was stirred under anitrogen atmosphere at reflux temperature over a Dean Stark trap for 18hours and the benzene was then removed by distillation. The mixture wascooled to room temperature, 1.73 grams (0.01 mol) 4-nitrophthalonitrilewas added, and stirring under nitrogen at 25° C. was continued for 40hours. The mixture was poured into 200 ml. of water and the product, awhite granular solid, was filtered and washed with water.Recrystallization from acetonitrile gave 2.10 grams of product (96.0%yield), melting point 233-233.5° C. The identity of the product as4,4'-bis-(3,4-dicyanophenoxy)biphenyl was established by infra red andby elemental analyses.

    ______________________________________                                                 Found        Calculated                                              ______________________________________                                        %C         76.4           76.74                                               %H         3.1            3.20                                                %N         12.7           12.38                                               ______________________________________                                    

EXAMPLE 3A

A mixture of 1.095 grams (0.0025 mol) of4,4'-bis-(3,4-dicyanophenoxy)biphenyl of Example 3, 5.61 grams (0.1 mol)potassium hydroxide, and 20 ml. of aqueous methanol was stirred at thereflux temperature of the mass for about one week. The mixture wasacidified with hydrochloric acid and the tetra-acid which precipitatedwas isolated by filtration, washed with water and dried in vacuum. Thistetra-acid was dehydrated by heating it at 275° C., and was thendistilled at 350° C. (0.1 mm.) to give 4,4'-bis(phenyleneoxyphthalicanhydride) melting at 286°-288° C. This composition which had theformula ##SPC10##

was identified by the following elemental analyses:

             Found        Calculated                                              ______________________________________                                        %C         70.2           70.3                                                %H         3.08           2.93                                                ______________________________________                                    

EXAMPLE 4

A mixture of 1.25 grams (0.005 mol) 4,4'-dihydroxydiphenyl sulfone, 0.4gram (0.791 gram 50.5% aqueous solution, 0.01 mol) sodium hydroxide, 20ml. nitrogen-sparged DMSO, and 20 ml. of benzene was stirred undernitrogen atmosphere at reflux over a Dean Stark trap for 18 hours andthe benzene was removed by distillation. The mixture was cooled to roomtemperature and 1.73 grams (0.01 mol) of 4-nitrophthalonitrile was addedand stirring was continued at room temperature (about 26°-28° C.) in airfor 40 hours. The homogeneous solution thus obtained was poured into 200ml. of water and the precipitate which separated was isolated byfiltration, washed with water, dried "in vacuo" and recrystallized fromacetonitrile. The product separated from the cooled solution as goldenneedles and was filtered and dried "in vacuo" to give 1.5 grams (60%)yield, melting point 229°-230° C. of4,4'-bis-(3,4-dicyanophenoxy)diphenylsulfone. The product was identifiedas such by infra red and by elemental analyses.

    ______________________________________                                                 Found        Calculated                                              ______________________________________                                        %C         66.6           66.93                                               %H         2.8            2.79                                                %N         11.3           11.14                                               %S         6.3            6.38                                                ______________________________________                                    

EXAMPLE 4A

When the 4,4'-bis-(3,4-dicyanophenoxy)diphenyl sulfone of Example 4 isreacted with potassium hydroxide and aqueous methanol and thereafteracidified with hydrochloric acid, and thereafter the formed tetra-acidis separated and dehydrated in the same manner as in Examples 1A, 2A,and 3A, there is obtained the corresponding dianhydride of the generalformula ##SPC11##

EXAMPLE 5

To a mixture of 1.73 grams (0.010 mol) 4--nitrophthalonitrile, 1.00 gram(0.005 mol) 4,4'-methylenediphenol and 1.38 grams anhydrous potassiumcarbonate was added 10 ml. nitrogen-sparged DMSO. The resulting mixturewas stirred for about 18 hours at room temperature and the poured intowater. The white precipitate which formed was collected andrecrystallized from ethanol-water to give 2.0 grams (80% yield)4,4'-bis(3,4-dicyanophenoxy)-diphenylmethane. The identity of thiscompound was identified by infra red and by elemental analysis.

    ______________________________________                                                 Found        Calculated                                              ______________________________________                                        %C         77.1           77.4                                                %H         3.5            3.13                                                %N         12.3           12.4                                                ______________________________________                                    

EXAMPLE 5A

The 4,4'-bis(3,4-dicyanophenoxy)diphenyl methane described in Example 5,can be treated with potassium hydroxide in aqueous methanol, acidifiedwith hydrochloric acid to yield the tetra-acid derivative, and thetetra-acid derivative can be dehydrated in the same manner as describedin Examples 1A, 2A, and 3A to yield the dianhydride of the formula##SPC12##

EXAMPLE 6

A mixture of 1.24 grams (0.01 mol) of 2-methyl hydroquinone, 3.46 grams(0.02 mol) 4-nitrophthalonitrile, 3.45 grams (0.025 mol) potassiumcarbonate, and 25 cc of dimethyl sulfoxide was stirred under a nitrogenatmosphere at about 25° to 30° C. for about 16 hours. The solution wasdiluted with 300 cc water and the solid material which separated wasfiltered and dried in vacuum to give 3.4 grams (about a 90% yield) of aproduct which when recrystallized from methyl isobutyl ketone yieldedwhite granules melting at 207°-208° C. and identified as thetetranitrile having the formula ##SPC13##

A mixture of 0.94 gram (0.0025 mol) of this nitrile, 5.61 grams (0.1mol) potassium hydroxide and 20 cc of aqueous methanol was stirred atthe reflux temperature for about 72 hours. The mixture was thenacidified with hydrochloric acid and a white precipitate which depositedwas filtered and dried in vacuum at about 100° C. The tetra-acid productso obtained was dehydrated by heating to 275° C. and then distilling at300° C. to give a colorless oil, which upon cooling gave a white solidmelting at about 214°-216° C. This material was identified as having theformula ##SPC14##

by the following analyses:

             Found        Calculated                                              ______________________________________                                        %C         66.6           66.3                                                %H         3.10           2.88                                                ______________________________________                                    

EXAMPLE 7

A mixture of 2.12 grams (0.01 mol) 4,4'-dihydroxy-3,3'-dimethylbiphenyl, 3.46 grams (0.02 mol) 4-nitrophthalonitrile, 3.45 grams (0.025mol) potassium carbonate, and 25 cc of dimethyl sulfoxide was stirredunder a nitrogen atmosphere at about 25° to 30° C. for approximately 16hours. The mixture was added to 300 cc of water and the resultingprecipitate was filtered, and dried in vacuum to give 4.5 grams (about a97% yield) of a tetranitrile which when recrystallized from methylisobutyl ketone yielded yellow granules melting at 238°-241° C. andhaving the formula ##SPC15##

About 1.35 grams (0.0029 mol) of this tetranitrile, 5.6 grams (0.1 mol)potassium hydroxide, and 20 cc aqueous methanol was stirred at refluxfor about 72 hours, the solution acidified with hydrochloric acid andthe precipitate which was obtained was filtered and dried in vacuum atabout 100° C. The resulting tetra-acid was dehydrated at 250° C. andthen distilled at 350° C. (0.1 mm) to give a product which upon coolingyielded a yellow solid melting at 246°-249° C. This was identified asthe dianhydride corresponding to the formula ##SPC16##

whose identity was established by the following analyses:

             Found        Calculated                                              ______________________________________                                        %C         71.2           71.1                                                %H         3.8            3.56                                                ______________________________________                                    

EXAMPLE 8

A mixture of 2.283 grams (0.01 mol) of bisphenol-A, 0.8 gram (1.6 gramsof a 50% aqueous solution, 0.02 mol) sodium hydroxide, 25 cc dimethylsulfoxide, and 15 cc toluene was stirred in a nitrogen atmosphere atreflux temperature over a Dean-Stark trap for about 15 hours. Theresidual mixture was then cooled to 25° C. and 3.46 grams (0.02 mol) of3-nitrophthalonitrile and 10 cc of dimethyl sulfoxide were added. Afterstirring for about 3 hours at 25° C., the mixture was added to 350 ccwater and the resulting precipitate was filtered, washed with water anddried in vacuum at 70° C. to give 4.8 grams (about 100% yield) of aproduct which when recrystallized from ethyl acetate gave silveryneedles having two sharp melting points: 161°-163° C., and 179°-180° C.(indicating polymorphism) for the tetranitrile derivative having theformula ##SPC17##

About 1.39 grams (0.0029 mol) of this bisphenol-A nitrile, 5.6 grams(0.1 mol) potassium hydroxide, and 20 cc of aqueous methanol was stirredat the reflux temperature of the mass for about 72 hours. The mixturewas acidified with hydrochloric acid and the formed precipitate wasfiltered and dried in vacuum. The reaction product was then stirred atreflux temperature with 7 cc of glacial acetic acid and 0.5 cc aceticanhydride. After cooling, the solids were filtered, and then dissolvedin a boiling toluene/acetic acid mixture, filtered hot and cooled. Theproduct which precipitated in the form of white granules melted at186°-188° C., and was identified as2,2-bis-[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride and havingthe formula ##SPC18##

by the following analyses:

             Found        Calculated                                              ______________________________________                                        %C         72.3           71.5                                                %H         4.5            3.85                                                ______________________________________                                    

EXAMPLE 9

Employing the same conditions as were used in the preceding examples,the tetranitriles prepared from the reaction of 4-nitrophthalonitrileand either 4,4'-dihydroxy-3,3',5,5'-tetramethylbiphenyl and4,4'-dihydroxy benzophenone can be hydrolyzed and dehydrated to give therespective dianhydrides having the formulas ##SPC19##

EXAMPLE 11

The tetranitrile derived from the reaction of 4-nitrophthalonitrile and4,4'-dihydroxydiphenyl sulfide, can be hydrolyzed to the correspondingtetra-acid and thereafter dehydrated to the dianhydride employing theprocedures described in the foregoing examples to give the dianhydridecompound having the formula ##SPC20##

EXAMPLE 12

The tetracyano derivative of tetrabromotetramethylbiphenol can beprepared similarly as in the foregoing examples by effecting reactionbetween tetrabromotetramethylbiphenol and 4-nitrophthalonitrile to givethe compound having the formula ##SPC21##

When the aforesaid tetracyano derivative is hydrolyzed to the tetra-acidderivative and then dehydrated using the procedures described in thepreceding examples, one obtains the dianhydride having the formula##SPC22##

EXAMPLE 13

The tetracyano derivative of the reaction product oftetrabromo-bisphenol-A and 4-nitrophthalonitrile was prepared bystirring at room temperature under nitrogen for 18 hours a mixture of3.46 grams (0.02 mol) 4-nitrophthalonitrile, 5.44 grams (0.01 mol) ofthe 2,2',6,6'-tetrabromo derivative of BPA, 6.9 grams (0.05 mol)potassium carbonate and 30 ml. DMSO. The mixture was then heated atabout 55° C. for a total of 50 hours, thereafter diluted with 600 ml. 1NHCl, filtered, the solid material air-dried and then dissolved in 500ml. benzene. After treatment with carbon for decolorizing purposes andfiltering, the solution was then concentrated to 400 ml., 200 ml.cyclohexane was added and the mixture concentrated to 300 ml. forrecrystallization purposes. The product which settled out was dried forabout 18 hours and on analysis was found to be the desired tetracyanoderivative having the formula (m.p. 251°-255° C.) ##SPC23##

The analyses were follows:

             Found        Calculated                                              ______________________________________                                        %C         47.2           46.8                                                %H         2.3            2.0                                                 %N         7.0            7.0                                                 ______________________________________                                    

When this tetracyano derivative is hydrolyzed and then dehydratedsimilarly as in the previous examples, one obtains the dianhydridehaving the formula ##SPC24##

The dianhydride compositions herein described have many uses. One of themore important uses to which these compositions may be put are asintermediates in the preparation of heat-resistant polyimides which havemany known uses. For instance, these dianhydrides may be reacted withvarious aromatic diamines such as 4,4'-diaminodiphenyl oxide,4,4'-diaminodiphenyl methane, 4,4'-diaminodiphenyl sulfone, etc., togive aromatic polyamide acids of the type more particularly described inU.S. Pat. No. 3,179,614, issued Apr. 20, 1965. These polyamide acids canthen be heated to cyclize the amide acid portions to give polyimideresins of the type described in U.S. Pat. No. 3,179,634, issued on thesame date as the preceding patent.

As a specific example, a polyimide preparation utilizing the dianhydridedescribed in Example 1A could be reacted, for instance, with4,4'-diaminodiphenyloxide to give the polyamide acid which upon heatingat elevated temperatures of about 150° to 250° C., is cyclized to givethe corresponding aromatic polyimide.

The polymeric composition derived from the reaction of dianhydridesherein described have many applications. These polymeric compositionsmay be used to form fibers, films, or molded products. Thus, either byextrusion from melt or by depositing from solution, fibers derived fromthese polymeric compositions may be formed and used in the preparationof various textile materials designed for clothing and similarapplications. In addition, solutions of the polymers can be used to coatelectrical conductors for insulation purposes.

The dianhydrides herein described and claimed also have utility ascuring agents for epoxy resins. When used for this purpose, they arecapable of accelerating the cure of such resins to form useful productsin the molded and electrical arts.

Various fillers may be incorporated in the polymeric compositions priorto molding thereof. Among such fillers may be mentioned glass fibers,carbon black, titanium dioxide, silica, mica, bentonite, etc. Moldedproducts derived from such a mixture of ingredients can be used asgears, handles for cooking utensils, etc. The incorporaton of abrasiveparticles such as carborundum, diamond powder, etc., makes moldedproducts derived from such polymeric compositions useful as grindingwheels, etc. The addition of carbon, silicon carbide, powdered metal,conducting oxides, etc., to the polymeric compositions results in theso-called resistance of semiconducting paints which have many usefulapplications.

The above-mentioned polymeric compositions can also be incorporated intoother materials to modify the properties of the latter. For example,they may be compounded with substances such as natural or syntheticrubbers, natural resins such as rosin, copal, shellac, etc.; syntheticresins such as phenol-aldehyde resins, alkyd resins, vinyl resins,esters of acrylic and methacrylic acid, etc.; cellulosic materials suchas paper, inorganic and organic esters of cellulose such as cellulosenitrate, cellulose acetate, cellulose ethers, such as methyl cellulose,ethyl cellulose, etc.

Laminated products may be made by superimposing organic or inorganicfiber sheet materials coated and impregnated with the polymericcompositions and thereafter bonding the sheets under heat and pressure.Shaped articles formed from such compositions under heat and pressure inaccordance with the practices now widely used in the plastics art have anumber of well-known applications such as in the decorative field,electrical board field, etc.

It will of course be apparent to those skilled in the art that otherconditions of reaction in addition to those specifically described inthe foregoing examples may be employed without departing from the scopeof the invention. Thus, it is apparent that many of the conditionsoutlined previously can be used for making the compositions hereindescribed and claimed. Also, it will be apparent that the ingredientschosen for making the desired reaction products can be varied widely,many examples of which have been given above.

What we claim as new and desire to secure by Letters Patent of theUnited States:
 1. The compound2,2-bis-[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride.
 2. Thecompound 2,2-bis-[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride.